In recent years, as electronic terminal devices such as a computer, a smart phone, a tablet PC, or the like have widely propagated, various types of electronic document related programs have been released, which enable reading, preparing, and editing the electronic document by using the electronic terminal devices.
The electronic document related programs include a word processor that supports preparation, editing, etc., of basic documents, a spreadsheet that assists input of data, an arithmetic operation, and data management, and presentation programs for assisting presentation by presenters.
In the related art, a user should read or prepare and edit the electronic documents by directly installing the electronic document related programs in the electronic terminal devices and thereafter, driving the electronic document related programs in order to read, prepare, and edit the electronic documents by using the electronic terminal devices.
However, in recent years, as an ultrahigh-speed Internet environment has been constructed and a wireless Internet environment has been constructed, which enables accessing the Internet anytime and anywhere, an electronic document related service is provided to the electronic terminal device as a client terminal through a server at a remote place, and as a result, a web based electronic document service has appeared, which enables reading, preparing, and editing the electronic document anytime and anywhere even though the user does not install a predetermined electronic document related program in the electronic terminal device.
The web based electronic document service is primarily used in enterprises or groups in that the web based electronic document service supports various client terminals to read, prepare, and edit the electronic documents through a browser installed in the client terminals after accessing an electronic document service providing server and supports various client terminals to perform simultaneous collaboration in real time with respect to electronic documents.
If the web based electronic document service may access the Internet without the need of installing the predetermined electronic document preparation program in the client terminal, since the web based electronic document service supports the electronic documents to be read, prepared, and edited through the browser mounted on the client terminal, mobility of the user may be guaranteed, and as a result, there is a tendency that personal users have gradually increased.
In general, when the web based electronic document service converts an original electronic document into a markup language based document and provides the markup language based document to the client terminal in order to support the client terminals connected through a network to edit the electronic documents through the browser, the web based electronic document service is operated in such a manner that the client terminal edits the markup language based document through the browser.
In this regard, in the web based electronic document service, a technology is required for supporting a plurality of users to perform simultaneous editing by simultaneously accessing one electronic document and in particular, a research into a technology is required for enabling a style changing operation to be appropriately performed when the plurality of users applies an editing command to change styles of corresponding objects to different styles with respect to the same objects among a plurality of objects including an image, a table, a text, and the like included in the electronic document.